Free Online Calculators
TDEE, protein, carbs & fat based on your goal
This macro calculator uses the Mifflin-St Jeor equation — one of the most accurate formulas for estimating your Basal Metabolic Rate (BMR). Your BMR is how many calories your body burns at complete rest. From there, the calculator applies an activity multiplier to find your Total Daily Energy Expenditure (TDEE), which reflects your real-world calorie burn based on how active you are.
Once your TDEE is established, your macronutrient targets — protein, carbohydrates, and fat — are distributed based on your selected goal. For example, someone with a TDEE of 2,400 calories who wants to build muscle might target around 210g of protein, 270g of carbs, and 67g of fat per day. These aren't random numbers — they're calculated ratios designed to support muscle protein synthesis, energy, and hormonal health.
If your goal is to lose weight, the calculator applies a moderate calorie deficit — typically 15–20% below your TDEE — while keeping protein high to preserve lean muscle. For a person with a 2,000-calorie TDEE, that could mean eating around 1,600–1,700 calories with roughly 160g of protein per day. Adequate protein prevents muscle loss that often accompanies calorie restriction.
For those looking to maintain weight, macros are set at TDEE with a balanced split that supports energy and recovery. And if you're focused on building muscle, a modest calorie surplus — around 10–15% above TDEE — gives your body the raw materials it needs for growth without excessive fat gain. This approach aligns with what's commonly called IIFYM (If It Fits Your Macros), a flexible dieting strategy that focuses on hitting daily macro targets rather than eating specific "clean" foods.
The question how much protein do I need comes up constantly in fitness communities. Most evidence points to 0.7–1g of protein per pound of body weight as a practical target for active individuals. A 175-pound person aiming to build muscle would therefore target roughly 140–175g of protein daily — something this macronutrient calculator factors in automatically.
Your macro targets are a starting point, not a rigid prescription. Track your intake for 2–4 weeks using a food logging app, then assess your progress. If your weight isn't moving in the expected direction, adjust calories by 100–150 per day before making larger changes. Small, consistent tweaks outperform dramatic overhauls every time.
You can use simple-calculator.online to recalculate your macros whenever your weight, activity level, or goal changes. As your body composition shifts, your TDEE changes too — recalculating every 4–8 weeks keeps your targets accurate and your progress on track.
BMR (Basal Metabolic Rate) is the number of calories your body needs to function at complete rest — breathing, circulation, cell repair. TDEE (Total Daily Energy Expenditure) adds your activity level on top of that, giving you a realistic daily calorie target.
The Mifflin-St Jeor equation is considered highly accurate for most adults, but individual metabolism varies. Use your results as a reliable starting estimate and adjust based on real-world progress over several weeks.
This calculator is for informational purposes only and does not replace professional medical or dietary advice. If you have a health condition, eating disorder history, or specific clinical nutrition needs, please consult a registered dietitian or physician before making significant dietary changes.